


Need You

by Diamondisbackbitch



Category: Voltron: Legendary Defender
Genre: Aftercare, Caring Shiro, Dubious Consent, M/M, Mermaid Sex, Rough Sex, Shatt, Siren!Shiro, mermaid au, mermaid!matt, trans Matt
Language: English
Status: In-Progress
Published: 2017-09-03
Updated: 2018-11-12
Packaged: 2018-12-16 03:09:04
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 2,851
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11819991
Author URL: https://archiveofourown.org/users/Diamondisbackbitch/pseuds/Diamondisbackbitch
Summary: Sirens are the most dangerous creatures in the ocean. Even more than sharks. They seduce you, fuck you, then eat you. If you see one then hide. You can never outrun a siren, just pray that it doesn't see you.





	1. Not getting eaten

**Author's Note:**

> A huge thanks to AllennellA for inspiring this work! This is the same basic AU as their work, Deep Sea Sinning, but not in the same continuity. I absolutely love that story, but I just really needed some Shatt in that au. so, after searching on every fanfiction site I know of and finding none, I wrote some myself.
> 
>  (This is very OOC plz don't yell at me)
> 
> *Cuts right to the porn without much of any storybuilding whatsoever bc it's midnight and I'm bored*

"Don't be scared, little merman," The siren said, caressing Matt's tail with his own, "I wouldn't hurt you. Why would I hurt you?" He leaned in closer, making Matt tremble with every touch. "I want to touch you, care for you, and make you feel good."

"P-please!" Matt begged, trying desperately to swim away from the siren's clutches. "Please," His voice broke in desperation, "I have a family to take care of, they need me!"

"Oh, Pretty, Pretty, boy," the siren whispered, "You're safe here, with me. I love you, I need you, please stay with me." He grabbed Matt's arms and pushed him back against the rocks. "I want you." He growled, his tail grinding against Matt's.

The rocks against Matt's back cut into him enough to draw blood. The siren's claws dug into his arms, effectively trapping him in place. He was going to get eaten alive. By the sexiest merperson he'd ever met, true, but still.

Hell of a way to die.

He screamed as he felt teeth sink into his shoulder. Anyone in the vicinity must've heard him, not that guards or a stray merperson could help much at this point. His vision was beginning to blur and his screaming was getting weak until he faded into darkness.

X X X X X X X X X

He woke up in a dimly lit cave, his tail and arms tied down with seaweed, loose enough to let him float up a bit, but tight enough he couldn't escape. Screaming wouldn't do him any good here, wherever he was. He knew every inch of neutral and Merpeople-controlled ocean. This HAD to be siren territory. Where else could he possibly be?

"Hello pretty boy." A smooth voice said.

Matt felt every scale he had begin to prick. Definitely siren territory. "What do you want with me?" He demanded, as fierce as he could manage.

"Needy food, who would've thought," The siren said dryly, all the smooth predatorialness gone from his voice, "I thought maybe I'd have some fun with you. You're awfully cute for a merperson, you know. Besides, I'm honestly not that hungry today." He shrugged.

Matt glared harpoons at him. "And what? You couldn't've just, I don't know, LEFT ME ALONE? Or did that thought just never happen to cross your tiny excuse for a brain?" He was shaking with pure rage. "I HAD A LIFE YOU KNOW! I HAVE A SISTER, SHE-" He went limp, choking back sobs, "She's gonna be- I can't leave her alone-"

"You're sob story isn't going to get me to let you go," The siren hissed, grabbing him and shoving him against the walls of the cavern, "You're FOOD, get it? I could not POSSIBLY care less about who's gonna miss you or what you 'could've done' with your life! You're life. Belongs. To. ME. Understand? ME."

"Just kill me, please."

The seaweed binding him loosened and the siren pulled Matt against him, twining their tails together. "Not hungry, remember? Don't worry, I have a feeling you wont have to wait long. After all, you look DELICIOUS," He grinned, running a hand up and down the length of Matt's body, "And from now on I think I'd like you to call me 'Master', understand?"

Matt sighed, "Yes, Master."


	2. Live For You

**Summary for the Chapter:**

> Warning: Stockholm syndrome
> 
> Also, the tags will fluctuate as I write on this

**Notes for the Chapter:**

> I'm sorry
> 
> .....
> 
> yeah.....
> 
> Let me know what you think and what should happen next! Your comments fuel me to write faster!

"Master!" Matt swam up to him eagerly. He'd been worried today when his master was home later than usual. His golden chain tugged back on his collar as he tried to swim out to him

Master laughed, staying just out of reach. "I've brought you a gift, baby," He brought a small net full of colorful fish from behind his back, "You help me get dinner, I'll let you have some too, okay?"

Matt bit his lip and blushed. He didn't like this part so much, but it was so rare he was allowed anything but kelp and other plants to eat, he'd do just about anything for those fish. "Yes master," He bowed low and submissive, "Anything, master."

"Holy fuck, you know I love that." Master brought him in for a deep and consuming kiss, the kind that made him moan in pure delight and forget for a moment he was nothing but a toy. Master didn't care about him, no really. This was all just a ruse to make him feel like he wanted to stay. Still, he kissed back, letting his whole body melt into the siren's touch.

Matt bowed his head softly when his master broke away. "How may I help you sir?" He purred, looking up at him through his lashes.

"Just do as I say." Shiro purred, unhooking Matt's chain as he put the fish down. "And stay next to me. If you try to run off I'll kill you." He reminded harshly as he grabbed Matt's arm and began swimming towards the rocks at the edge of Siren territory where daring mers liked to hunt. "Lay on the rocks and scream for help." He growled and pushed Matt down, digging his fangs into the healing wound on Matt's shoulder until it bled profusely. "Get someone to come over for help." He ordered before disappearing.

Matt nodded, tears prickling in his eyes from the pain and he released a sob. "Help! Please! Please someone help!" He screamed, clutching at the bloody flesh in desperation to stop the blood. He hated blood.

X X X X X X X

"Matt!" Pidge screamed when she heard his voice. She swam as fast as she could toward his voice. "Matt! Oh my god.." her eyes widened in horror when she saw the blood flowing from his shoulder.

Matt stopped screaming for help and turned pale. "Pidge no.... no you have to run...." He whispered, eyes darting around trying to see if Shiro was looking. "Go!"

"What...?" Pidge frowned, taking her brother's arm and tugging him off the rock. She planned on taking him back to the city where they'd be safe, but she backed up a few more inches and her back hit someone's chest. Someone... very large. With smooth scales and sharp fins...

Oh no...

"Quite the catch...." Shiro grinned, pinning the mer's arms to her sides and licking his sharp fangs.

Matt whimpered and darted to his master's side. This was bad. "Master please, don't eat her... I swear I'll do anything please..." He sobbed and buried himself under Shiro's chin.

"What the fuck?" Pidge growled, struggling against the siren. "Matt get away from him! He's a siren, he'll kill you!" She screamed as his claws dug into her flesh. "He... He hasn't... this is where you've been." She whispered, horrified.

"So you're the sister Pet likes to talk about, aren't you?" Shiro laughed, nuzzling Matt back. "He cares about you a lot to stand up to me like that. Don't worry though, he'll be firmly punished. You however..." He sighed and looked down at Matt's sobbing body. "I won't eat you. For /now/." He growled, letting her go. "But if you ever come near enough to me again don't think I'll hesitate. Now get out of here, I'm hungry."

Pidge rubbed her bleeding arms and glanced between the siren and her brother. "I'm not leaving without him." She snarled, taking Matt's arm and dragging him back into mer territory. "Guards! Siren!" She screamed, praying someone was within earshot to help them. Holding her brother as tightly as she could, she began to swim as fast as she could.

Shiro growled and darted after her, catching up in seconds. "Drop him. Now. I gave you a chance to leave unharmed and I'll offer it one last time. Leave." He grabbed Matt's other arm and tugged him back, tail curling around the mer's. "He's mine."

Matt whimpered and looked between the two, not really sure who to go with. He was Shiro's through and through. He /liked/ being with Shiro. But Pidge... He'd do anything for her.

"Please go." Matt whispered to his sister. "I'm fine, I promise, but I need you to leave. He'll hurt you, please..." He begged, pulling away from her.

"I trust you." Pidge whispered back, trembling in fear. This was a horrible idea. What if she never saw Matt again? What if that siren ate him? She turned away and began swimming as fast as she could away from them.

Matt watched her sadly and trying not to cry. He was glad Pidge would be safe, but it still meant he'd never see her again.

"Shhh, shh, it's okay Pet." Shiro purred and swam them back into siren territory. "You're safe now with me. She won't be hurt as long as she stays away." He promised.

Matt nodded and hugged him. Maybe he was a siren and utterly terrifying, but at least he felt like home. "Thank you master."

"You're welcome P-"

"Halt!" a mer guard held his spear out in front of him, glaring at the siren. "Release the mer immediately and you will face no harm!"

Shiro growled and flared out his fins. "Get down pet, I don't want you watching this." He waited until Matt had dove behind the rocks and turned away before launching forward to attack the mer; ripping him into bloody pieces and devouring every bit.

**Notes for the Chapter:**

> don't forget I have a Patreon now! https://www.patreon.com/diamondstuff originally I wouldn't post anything on here for the next month, putting it one there instead. (after this chapter new ones will be on there for a month before they're posted on here. Along with exclusive works and art!)


	3. Chapter 3

**Summary for the Chapter:**

> I was reminded this story existed so guess what? You get more!

Shiro sighed as he took his pet back to the cave that he called home. It wasn't much, but it had always been enough for him. Or it used to. He wasn't quite sure anymore.

Matt, or 'pet' as he preferred to call him, was his soft spot. Seeing him sobbing for his sisters life was almost enough for him to simply release the mer, but not truly. He couldn't give him up after so long together. What would he do with his life then? But he'd spare his family. Every single time if he had to because he knew just from meeting her once that sister of his would be back. And if he could help it, for Matt's sake, he try not to hurt her.

Sighing as he brought himself from his thoughts, Shiro watched ad Matt devoured the last of the fish he'd brought. Catching fish was something quite new and he still wasn't terribly good at it, but every day when he brought food home the mer would act like an overjoyed puppy with the gift.

"Let's get you to sleep now, shall we? It's been quite a day for both of us." Shiro smiled, laying back on his bed and patting for Matt yo join him. A rare treat he reserved for when Matt had behaved himself well.

Matt squealed happily and snuggled next to him. For such a shy little thing he was quite a cuddler, not that Shiro minded all too much.

They lay together for a good while, Shiro believing his bed partner had fallen asleep as he gently curled his tale over him. A sign of love and devotion amount sirens, though he had doubts of what it meant to mers, when without warning Matt spoke.

"Thank you. For sparing my sister's life." He mumbled. "I know it probably doesn't mean that much to you, but she's my little sister. I don't know what I'd do if something happened to her, so... thank you."

Shiro chuckled and kissed Matt's neck. It had been weeks since the mer had spoken that much at once and to be honest it was nice. "You're welcome. I couldn't stand to see you cry like that my pet. I can't promise not to harm her of she comes back, but you have my word that I will not kill her. No matter what she does." He promised. Wrapping his arms tighter around Matt.

Matt smiled softly. "Thank you master."

**Notes for the Chapter:**

> Fun question: do you want more horror or more fluff?


	4. Chapter 4

**Summary for the Chapter:**

> As much as I love mpreg and soft pregnant cuddles you know what's better? Adopting smols and growing together as a couple.

**Notes for the Chapter:**

> I hate this chapter. It doesn't match my writing style well and the feel is different than the other chapters. I'm sorry and I don't know what to do, but I'm trying to update my fics and possibly finish as many as possible, so here you go

"I'm going out." Shiro smiled, slipping the golden collar and chain around Matt's neck. "Stay here. I'll see you in a few hours." He kissed Matt's cheek gently.

Matt chirped and reached up to kiss him back. "Yes sir." He promised.

"Good boy." Shiro smirked and swam off. He didn't have anything to do that day, but he needed time to think. Originally he was just going to eat Matt. Then he'd planned to keep him for a bit before deciding what to do with him. Maybe give him to someone else. But now... He had to keep him. But eventually Matt would be unhappy, possibly already was, without his family.

He had to do something about this. Shiro groaned and sat on a rock, looking around him. He wasn't sure where he was to be honest. He'd never swam this far before. Shit, what if he was inside the mer borders?

He looked around, trying to find any signs of mers or guards. Nothing. For now at least. Shiro sighed and sat down again. He'd need to get back without anyone spotting him either. And-

A small cry sounded from the rocks below him. Startling him enough to slide off the rocks.

"Who's there?" Shiro growled, baring his teeth as he swam downward towards the noise. It might be a trap, sure, but it sounded a whole lot like a child. And he wasn't cruel enough to leave a child hidden and abandoned in the rocks.

The cry sounded again, helping Shiro find the small child wrapped in a blanket and tucked into a hole in the rocks. It was barely moving, obviously weak and unable to survive.

"Poor thing." Shiro frowned, taking the tiny mer into his arms. "Here, lets get you something to eat." Mer babies usually drank milk from their mothers, but obviously that wasn't an option. But some places sold alternatives. Surely a shop in the Siren waters would sell some form of it. All he had to do was get back into his own territory without being spotted.

Shiro took a deep breath and shifted the blanket so the tiny mer could breathe better as he swam. He'd have to just go as fast as possible and hope nobody spotted him as they hadn't on the way there. So he swam. As fast as he could manage back to Siren territory, thanking his lucky stars no mers noticed him.

X X X X X X X

"I need something to feed this." Shiro motioned to the bundle of blanket and mer. "Please don't ask, I just need to know what to feed it and where to get it." Shiro was in front of a shop owner. The only one in the area that dared trade and buy from mers.

Coran twisted his mustache and looked down at the baby. "Alright. No questions. But I do have some formula if you want to buy that. But it'll go pretty quick. If you're willing to pay ten percent now I'll buy you plenty more in a few days. You'll need to ration the stuff I give you since it won't last that long if you don't." He warned, taking out a case of bottles full of green-ish pale liquid. "That's twenty three gac for these and fifteen gac if you want me to buy you sever weeks worth next time."

Shiro handed over the money without hesitation. "Please." He took the case in one hand, shifting the baby to be held in one arm. "Thank you Coran. I'll be back in a few days to get more formula." He promised, swimming back to his home. It hadn't been that long honestly, but this baby needed food and soon.

"Shiro?" Matt frowned, watching him come in. "What have you got there?"

Shiro set the baby down on his desk and took a bottle of the formula. "A baby. It was abandoned on the western rocks."

"That's mer territory." Matt swam over and looked down at the baby, a tiny brown haired girl with huge green eyes and a pale gold tail. Looked half starved, but alive.

"I know." Shiro sighed. "I... I don't know how to get this thing to eat." The mer was refusing the bottle every time he tried and it was getting frustrating. It needed to eat, why wouldn't it!

Mat chuckled and took the mer and bottle from Shiro. "She's just nervous. Probably confused about her surroundings." He took her back to the bed and gently bounced her, cooing softly until she giggled with laughter. "See? She's fine." The baby took the formula easily after that. Allowing Matt to hold her close while he fed her. "And don't call her a thing. She's a baby, Shiro, not an item."

Woah. Shiro stared at Matt, a bit confused. Usually nowadays Matt was so submissive he barely talked or even moved without Shiro's permission. What was going on? "Do you want to name her then?" Shiro asked, swimming over to the bed and sitting next to Matt. "I don't really know what to do with her, but I... Well it would be cruel to leave her to die I guess, so she's here now. With us."

"Abagail." Matt smiled. "And thank you Shiro. It was a good thing you did; saving her."

"Thanks." Shiro muttered. "Pet."

Matt's eyes widened when he realized. "Oh f-"

**Notes for the Chapter:**

> so, was Matt faking it? just slipped out of that part of his personality once there was a smol around? who knows, definitely not me.

**Author's Note:**

> apparently 'Predatorialness' is not a real word. I meant it like 'his voice made him sound like a predator who was hunting you' if you were confused.
> 
> (It also said that 'couldn't've' wasn't a word??? What?? Is???? This???/??? Bullshit???)


End file.
